SAIL 



77 



less strength, when on either beam. The action 

 of the wind on an oblique sail is a good example 

 of what is known in mechanics as ' the composition 



and resolution of forces.' Let TD, fig. 2, be a 

 ship, PAS its sail, \VA the direction of the wind, 

 ana let the length of WA represent the pressure of 

 the wind on the sail. WA can be resolved into AB 

 perpendicular to the sail, and B\V parallel to it, the 

 latter of which has no 

 effect in pressing on 

 ' the sail ; therefore AB 

 is the effective pres- 

 sure on the sail. Were 

 the vessel round, it 

 would move in the 

 direction BA. Let BA 

 be resolved into CA 



and BC, the former, CA, acting in the direction of 

 the keel or length of the vessel, or in the direction 

 CAD, and the Tatter perpendicular to it, or in the 

 direction of the breadth. The former pressure, CA, 

 is the only pressure that moves the vessel forward, 

 the other, BC, makes it move sideways. From the 

 form of the vessel, however, this latter force, BC, 



Fig. 3. Sails of a Cotter Yacht, with the name* of the 



different part* : 

 MAlifSAli., A. 1, main-tack ; 2, main-tack tackle; 3, main-tack 



tricing-linc ; 4, neck or throat; 5, peak: 6. clew; 7, bead; 



8, leach; 9. luff; 10, foot; 11, strengthening piece*; 12, 



cringles ; 13, reef pennants rove ; 14, main clew lashing: 15, 



mat hoops and seizings ; 16, peak earing ; 17, reef knittles or 



issMs, 

 OArr-TonuiL, B. 18, head; 18, peak; 20, clew; tl, foot: 22, 



tack ; 23, luff; 24, leach ; 25. peak earing : 26, head earing. 

 FORESAIL, C. 27, fore- tack ; 28, clew: 29, head: SO. foot; 31, 



luff; 32, leach; 33, reef knittles or points; 34, fore-tacit 



tackle rove through a sheave In stem-head. 

 JIB, O. 35, tack, hooked on to the traveller; 36. clew; 37, 



head ; 38, toot; 39, luff; 40, leach ; 41, inhaul of the traveller. 



produces comparatively little lateral motion ; any 

 that it does occasion is called leeway. It results, 

 therefore, that with the wind exerting an obliqur* 

 pressure, the actual progress will lie to the power 

 of the wind only as CA is to WA. 



Sails may practically be divided by their shape 

 into the approximately triangular and approxi- 

 mately square ; and according as they are set 

 parallel to the keel of the ship or across the ship, 

 tli> \ :ire fore-and-aft sails or square sails. The 

 KaiU whidi are set square across the ship are not 

 exactly, but nearly, square in shape. But many 



fore-and-aft sails are also nearly square, or at least 

 four-sided ; the chief exception to this being xtuit- 

 sails, which are purely triangular, and are sus- 

 pended on the ropes which stay the masts upon the 

 foresides from the jib-boom, bowsprit, and deck 

 in the case of the foremast, and from the deck in 

 the case of the mainmast. Two of these staysails, 

 the fore-staysail and the jib, are common to most 

 types of Ixiats referred to in this article. 



The larger sailing-vessels are usually propelled 

 by a combination of fore-and-aft and square sails 

 in varying number; the name and position of 

 these are illustrated at the article SHIPBUILDING. 

 The Schooner (q.v. ) has mainly fore-and-aft sails 

 on both masts, though the square-topsail schooner 

 carries square topsails. The two-masted Brig 

 (q.v.) is mainly square-rigged ; and the brigantine 

 is a cross between brig and schooner. The Cutter 

 (q.v.) is the typical fore-and-aft one-master. The 

 names of the several sails, and the technical terms 

 for the parts of the sails, will be gathered from 

 the accompanying illustration (tig. 3). A sloop 

 is supposed to have a 

 fixed bowsprit, whereas 

 that of the cutter is a 

 running one. A i/nirl 

 has a foremast rigged 

 exactly like a cutter, 

 but has a small mizztm- 

 mast carrying a siinnl, < r 

 or ilrirer. See YACHT. 



Some other types of 

 Bail not shown in the 

 figures in the articles 

 referred to may be noted 

 here. The lug-sail, a 

 four-sided sail hung 

 from a yard fastened 

 obliquely to the mast, 

 about one-third of ite 

 length from the one 

 end. Luggers may be one, two, or three masted, 

 and may accordingly vary much in size. The 

 typical shotUder-of- mutton sail is a triangular 

 sail set on a boat's mast ; the tip is some- 

 times made into a separate gaff-topsail. The 

 sprit-sail is 

 a quadrangular 

 sail stretched 

 from the mast 

 by help, not of 

 a gaff along its 

 top, but by a 

 sprit extending 

 from the foot 

 of the mast 

 diagonally to 

 the upper aft- 

 most corner of 

 the sail. The 

 London barge 

 has its heavy 

 mainsail partly 

 supported by a 



sprit, and there is a spanker on a small mast 

 behind ( see Vol. VI. p. 702). The spinnaker is a 

 jib-like racing sail carried by yachts, and extended 

 to catch the wind on the side opposite the mainsail. 

 Many American centre-board boats carry one large 

 quadrangular fore-and-aft sail only, the mast rising 

 out of the IH>W of the boat. 



The Intern sail, much used in the Mediterranean, 

 is a triangular sail stretched from a long yard 

 attached to a short mast, as shown in fig. 6. 

 The felucca is a two-masted lateen-sailed boat; 

 the sails of the Egyptian dahabeeah and of the 

 Arab dhow are of the same type. A xebec 

 carries a combination of lateen and square sails. 



Fig. 4. Lag- 



V 



F * 5-- 



